Of all the directors who might have been hired to follow super-hot boy band One Direction around on tour for their upcoming concert movie, "One Direction: This Is Us," Morgan Spurlock is not the obvious choice. A filmmaker best known for his 2004 stunt documentary "Super Size Me," (where he spent a month ruining his body by only eating McDonald's and recording the results) Spurlock is a showman at heart, but he doesn't exactly swim in the mainstream.

So maybe the real question is this: Even with the chops and the resume to make a 3-D concert movie, why would Spurlock want to?

The answer lies in Spurlock's oeuvre: Along with "Super Size Me" and projects like 2007's "What Would Jesus Buy" and 2012's "Mansome," it's clear that the 42-year-old director is obsessed with consumers' obsession with products. And One Direction — a band cobbled together by Simon Cowell on “X Factor” — is arguably not unlike a Big Mac: Pre-packaged, served up for the hungry masses, and ultimately irresistible.

Spurlock agrees. "It makes sense with the way my film career has gone, and what I've made," he says. "I've made very populist movies … from fast food to terrorism to advertising. I feel like people look at what I've done as making things accessible. So if you have a band with a core audience, I could add something new to that; I could bring a different vision to that.”

Fortunately, he said, the boys in the band were receptive to the behind-the-scenes look he wanted to take. “The people who see this film need to feel like they’re having moments they would otherwise never get with them,” he said. “So for them to have that trust in me from the beginning, that was important.”

Spurlock says he has a lot of respect for the members of One Direction, who have to endure a grueling schedule. “I don’t think people realize how much effort goes into being a global pop star,” he says. “From the minute they wake up until the minute they go to bed, their whole calendars are managed out. It’s bang, bang, bang all day.”

Sometimes, that crazy schedule led to having to turn the cameras off. Spurlock says that’s part of the trick of making a movie like this — knowing when to keep them running, and when a band member might need a break. “There are times where it’s like, ‘I just need some time, I need to not have a camera in my face for a while,’” he says. “Sometimes, you push through that discomfort and get great stuff. Luckily there were five guys in the band, so no one ever felt they were under the microscope for extended periods of time.”

Spurlock wasn’t exactly a One Direction groupie before signing on to direct (though he acknowledges that “What Makes You Beautiful” was unavoidable in 2011), but he underscores that someone does not have to be a fan to enjoy “This Is Us.”

“This film is so fun, I can’t tell you how many non-fans I've talked to who said they went into the film not wanting to like it, but it turned out to be so much fun,” he says. “These guys are disarmingly charming. I challenge you to not like them when it’s over. They are so likable, and more than anything else they are completely normal. They have yet to become jaded by this machine they’re on.”

An example? Spurlock remembers being at a UK press event with the band, and noting how they were the first to introduce themselves when they came into a room. “And then they were making tea for the people they were talking to!” he chuckles. “You can’t teach being humble, or having humility. That’s something instilled in you in your upbringing.”

Would he rather have been making a film with a band closer to his own heart? Maybe. The thing is, as Spurlock notes, "I didn't get approached to make a movie with Metallica. Sometimes you've got to open the door to who knocks on it."